Amplifier



FIG. 1 is a front, top, right perspective view of the front side of an amplifier;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a back elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines shown on the drawings depict portions of amplifier that form no part of the claimed design. 

CLAIM The ornamental design for an amplifier, as shown. 